/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.spark.sql.execution.datasources.parquet;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.Path;
import org.apache.parquet.HadoopReadOptions;
import org.apache.parquet.ParquetReadOptions;
import org.apache.parquet.format.converter.ParquetMetadataConverter;
import org.apache.parquet.hadoop.ParquetFileReader;
import org.apache.parquet.hadoop.metadata.ParquetMetadata;
import org.apache.parquet.hadoop.util.HadoopInputFile;

import java.io.IOException;

/**
 * `ParquetFooterReader` is a util class which encapsulates the helper
 * methods of reading parquet file footer
 */
public class ParquetFooterReader {
  public static ParquetMetadata readFooter(Configuration configuration,
      Path file, ParquetMetadataConverter.MetadataFilter filter) throws IOException {
    return readFooter(HadoopInputFile.fromPath(file, configuration), filter);
  }

  public static ParquetMetadata readFooter(Configuration configuration,
      FileStatus fileStatus, ParquetMetadataConverter.MetadataFilter filter) throws IOException {
    return readFooter(HadoopInputFile.fromStatus(fileStatus, configuration), filter);
  }

  private static ParquetMetadata readFooter(HadoopInputFile inputFile,
      ParquetMetadataConverter.MetadataFilter filter) throws IOException {
    ParquetReadOptions readOptions =
      HadoopReadOptions.builder(inputFile.getConfiguration()).withMetadataFilter(filter).build();
    // Use try-with-resources to ensure fd is closed.
    try (ParquetFileReader fileReader = ParquetFileReader.open(inputFile, readOptions)) {
      return fileReader.getFooter();
    }
  }
}
